Streetwise

April Is the New May

Investors are worried that the Fed's monetary aid is losing its punch. Fearing a drop in stocks, they're piling into defensive sectors.

A stock market delivered from the brink of depression to record highs in four quick years can be a bundle of insecurities. What happens if the central bank stops cosseting us, and how will it pare back its trove of Treasuries as rates rise? Lately, however, such perennial questions are pushed aside by more pressing concerns.

Last week's 1% pullback has revived fears—altogether now—that the Federal Reserve's monetary medicine is losing its oomph. The Fed's still printing gobs of money, but U.S. manufacturing and services...